CA2068749A1 - Pulverized absorbent material for aqueous liquids based on a water-swellable polymer - Google Patents
Pulverized absorbent material for aqueous liquids based on a water-swellable polymerInfo
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- CA2068749A1 CA2068749A1 CA002068749A CA2068749A CA2068749A1 CA 2068749 A1 CA2068749 A1 CA 2068749A1 CA 002068749 A CA002068749 A CA 002068749A CA 2068749 A CA2068749 A CA 2068749A CA 2068749 A1 CA2068749 A1 CA 2068749A1
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- Prior art keywords
- water
- polymer
- swellable
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-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
- A61L15/00—Chemical aspects of, or use of materials for, bandages, dressings or absorbent pads
- A61L15/16—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons
- A61L15/42—Use of materials characterised by their function or physical properties
- A61L15/60—Liquid-swellable gel-forming materials, e.g. super-absorbents
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/22—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising organic material
- B01J20/26—Synthetic macromolecular compounds
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F8/00—Chemical modification by after-treatment
- C08F8/30—Introducing nitrogen atoms or nitrogen-containing groups
- C08F8/32—Introducing nitrogen atoms or nitrogen-containing groups by reaction with amines
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F2800/00—Copolymer characterised by the proportions of the comonomers expressed
- C08F2800/10—Copolymer characterised by the proportions of the comonomers expressed as molar percentages
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- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Epidemiology (AREA)
- Life Sciences & Earth Sciences (AREA)
- Medicinal Chemistry (AREA)
- Analytical Chemistry (AREA)
- Dispersion Chemistry (AREA)
- Hematology (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- General Chemical & Material Sciences (AREA)
- Polymers & Plastics (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
- Polyamides (AREA)
- Solid-Sorbent Or Filter-Aiding Compositions (AREA)
- Compositions Of Macromolecular Compounds (AREA)
- Processes Of Treating Macromolecular Substances (AREA)
- Absorbent Articles And Supports Therefor (AREA)
Abstract
A B S T R A C T
A powdery absorbing material for aqueous liquids based on a water-swellable powdery polymer with at least 0.2 equivalents carboxyl groups per 100 parts by weight which are neu-tralized by 50 to 99, advantageously by at least 80 mol-%. The absorbent is obtained by treating the wa-ter-swellable carboxyl-groups-containing polymer with a solution of an N-(hydroxyalkyl).beta.-(meth)-alanine es-ter or with the polycondensation products thereof. As solvent for the agent water is used which either com-prises water-miscible organic diluents evaporating on heating the mixture, or non-evaporating ones, i.e., diluents remaining in the polymer.
A powdery absorbing material for aqueous liquids based on a water-swellable powdery polymer with at least 0.2 equivalents carboxyl groups per 100 parts by weight which are neu-tralized by 50 to 99, advantageously by at least 80 mol-%. The absorbent is obtained by treating the wa-ter-swellable carboxyl-groups-containing polymer with a solution of an N-(hydroxyalkyl).beta.-(meth)-alanine es-ter or with the polycondensation products thereof. As solvent for the agent water is used which either com-prises water-miscible organic diluents evaporating on heating the mixture, or non-evaporating ones, i.e., diluents remaining in the polymer.
Description
20687~9 PULVERIZED ABSORBENT MATERIAL FOR AQUEOUS LIQUIDS BASED
ON A WATER-SWELLABLE POLYMER
The present invention relates to a powdery absorbent for aqueous liquids which is based on a water-swell-able polymer not setting up on contact with water or aqueous solutions, such as body liquids, i.e., said water-swellable polymers do not impede the absorption of further liquid by forming a barrier of swollen gel particles and they maintain their swelling capacity under load, as is the case when the polymers are used in diapers or incontinence articles, to a large ex-tent.
The manufacture of water-swellable polymers is known.
A typical method of producing water-swellable polymer particles by inverse suspension polymerization of an aqueous solution of acrylic acid and alkali or ammoni-um acrylate in a hydrocarbon and cross-linking the polymer is described in U.S.-Patent No. 4,698,404.
European patent application No. A1 0 205 674 describes the solvent polymerization of monomers substantially containing acid groups in the presence of an agent having a cross-linking action. After the acid sroups of the polymer have been neutralized by at least 27%
and the polymer gel has been dried, a water-swellable polymer is obtained which has a high gel strength and small amounts of extractable components.
European patent application No. A2 0 312 952 describes the polymerization of carboxyl-groups-containing mono-mers neutralized by at least 20% in the presence of dispersed cross-linking agents.
The continuous copolymerization of an acrylic-acid-comprising monomer solution, wherein the acrylic acid is neutralized by at least 20%, is described in Euro-pean patent application No. A2 0 280 541.
To improve the technical application properties of wa-ter-swellable polymers selected from the group con-sisting of a cross-linked hydrolyzate of an acrylamide copolymer, a hydrolyzate of a cross-linked acryloni-trile copolymer, a cross-linked, partially neutralized acrylic acid polymer, or to adapt them to their par-ticular function, the polymers are frequently sub-jected to a secondary treatment.
European Patent Nos. O 009 977 and 0 001 706, for example, describe the surface coating of particle-shaped water-swellable polymers with hydrophobic com-pounds or polyethers to improve the dispersibility in blood.
U.S.-Patent No. 4,587,308 describes the secondary cross-linkage of water-swellable polymers, dispersed in slightly swollen form, with diglycide ethers, poly-valent metal salts or halogen epoxy compounds.
German OS [Offenlegungsschrift, publication of a Ger-man patent application] No. 34 29 379 describes a wa-ter-absorbing resin obtainable by impregnating a wa-ter-swellable resin with a hydrophilic, reactive, ole-finically unsaturated monomer, or polymer thereof, and a cross-linking agent.
.. . .
U.S.-Patent No. 4.666,975 describes the post-cross-linkage of water-swellable polymers in suspension by reaction with diglycide ethers.
GB 21 19 384 A claims the secondary cross-linkage in the particle surface of water-swellable polymers, the carboxyl groups of which are neutralized to 50 to 99 mol-%, with multifunctional compounds, such as polyols or polyamines.
The secondary cross-linkage in the polymer surface with solutions of polyols is described in DE-OS 35 23 617. The aftertreatment is carried out with polymers whose carboxyl groups are neutralized by 50 to 99 mol-% in the presence of water and a hydrophilic organic solvent.
All these processes strive for improving the liquid transport in a layer of polymer particles or providing a polymer which~ after swelling, does not release the stored liquid on exertion of pressure, e.g., by an in-fant's body on the swollen polymer within a diaper.
However, it is the object not only to improve the liq-uid transport in a layer of water-swellable polymer particles or the capability of the polymer to retain liquid under subsequent pressure when the polymer could swell freely, i.e., without load, but also to provide a water-swellable polymer which is capable of absorbing liquid even against a load. This special ab-sorption property is referred to as absorption under pressure/load in the European Patent O 339 461.
It has been found that water-swellable, carboxyl-groups-containing polymers 50 to 99 mol-% of which are present in neutralized form can be obtained with a ' - ~ ' ' ' :
- , :
high swelling capacity under load, if water-swellable polymers with a low swellability under load are-treat-ed with N-(hydroxyalkyl)~-(meth)-alanine esters and/or the polycondensation products thereof and heated.
It has additionally been found that the elevated-tem-perature secondary treatment of carboxyl-groups-con-taining polymers - which are neutralized by more than 80 mol-% - with polyols or amino alcohols does not, or only under impracticable conditions, result in prod-ucts with improved properties, but that, in contrast to this, treating said polymers neutralized by more than 80 mol-% with N-(hydroxyalkyl)~-(meth)-alanine esters and/or the polycondensation products thereof at elevated temperatures may result in an increase of the swelling capacity under load.
An additional technical advantage of the secondary treatment of water-swellable polymers with N-(hydroxy-alkyl)~-(meth)alanine esters and/or the resulting polyamide or polyamide ethers thereof results from the fact that lower aftertreatment temperatures with a mo-larly identical feedstock of aftertreatment agent or shorter secondary treatment periods at the same tem-perature are necessary to improve the product proper-ties, this is in contrast to the use of polyols or al-kanolamines according to the methods of GB 21 19 384 and DE-OS 35 33 617.
The production of N-(hydroxyalkyl)~-(meth~alanine es-ters and their capabil.ity of forming polyamides or polyamide ethers already at room temperature are de-scribed in detail in Journal of Polymer Science , Part A-1, vol. 6, 1195-1207 (1968) and vol. 7, 889-898 (1969).
The production is carried out by the Michael reaction of alkanols or alkanolamines at (meth)acrylic acid es-ter.
The quantity of N-(hydroxyalkyl)~-(meth)alanine esters and/or their polycondensation products used according to the present invention amounts to 0.001 to 5 p/wt (parts by weight), relative to 100 parts of water-swellable polymer. If more than 5 p/wt are used, the extent of decrease in the swelling capacity (reten-tion) of the polymer is too 'large. The swellability under load is not improved, if the charge is below 0.001 p/wt.
The aftertreatment agents according to the present in-vention are used in aqueous solution. The water serves to dissolve the alcohol-insoluble solid polyamides of the N-(hydroxyalkyl)~(meth)alanine esters and, at the same time, as vehicle for the aftertreatment agents into the water-swellable Polymer particles. The quan-tity of water amounts to 0.1 to 5 p/wt per 100 p/wt of water-swellable polymer. Since the water-swellable polymers which have not been re-treated would set up on contact with the aqueous solutions of the after-treatment agent, additional water-soluble organic di-luents are used in amounts of 0.2 to 10 p/wt per 100 p/wt of water-swellable polymer. The following sub-stances are used as water-soluble organic diluting agents:
a) those evaporating from the solution of the second-ary treatment agent and the water-swellable polymer on heating said mixture, e.g., monofunctional alcohols having the C-number 1-4, acetone, glycol ether, glycol ester and/or b) those which do not evaporate on heating and remain on or in the polymer particle, e.g., butyrolactone, butyrolactam, lactic acid, diacetin.
Since the diluents stated under a) are inflammable and form explosive mixtures which must not come to the at-mosphere, they require some technical measures when the secondary treatment of the water-swellable poly-mers is carried out.
The diluents stated under b) remain on the polymer and do not require special protective measures. However, they may negatively influence the swelling capacity of the aftertreated polymers, when used in larger amounts during the secondary treatment.
The amount of added water-soluble organic diluting agent depends on the amount of water employed. The quantity should be determined such that, after mixing with the water-swellable polymer, a product results which is easy to handle and does not contain aggluti-nated particles.
The solution of the preparation is mixed with the pow-dery, water-swellable, carboxyl-groups-containing pol-ymer and subsequently heated. The powdery polymer may have a spherical shape, obtainable by polymerization of emulsified aqueous monomer solutions, or an irregu-lar shape, obtainable by solvent polymerization, e.g., of a 30% monomer solution comprising 50 to 99 mol-%
alkali acrylate, 50 to 1 mol-% acrylic acid and 0.01 to 0.5 %-wt. of an agent having a cross-linking ac-tion. The particle size of the water-swellable polymer to be treated amounts to 0.05 to 1 mm, preferably 0.1 to 0.8 mm.
20687~9 The mixture consisting of the solution of the agent and the water-swellable polymer is manufactured in the laboratory with ordinary mixers, such as those used in the household. In large-scale production, blade mixers or paddle mixers operating continuously or discontinu-ously are used. The solution of the agent is evenly dosed to the powder preparation or into the powder stream.
The mixture of dissolved, di~uted preparation and wa-ter-swellable polymer is subsequently heated to 100 to 250C, preferably 150 to 210C. The heating tempera-ture and time depend on the amount of agent, with the treatment time in general amounting to at least 5 min.
up to one hour.
The amount of preparation, the mode of feeding, and the treatment temperature are advantageously coordi-nated in such a way that the duration of treatment permits a continuous performance of the process, i.e., that the required heat-up time does not result in too long dwell times within the dryer and the subsequent cooler. Suitable dryers are, e.g., the drying cabinet or the disk dryer.
A water-swellable polymer giving a dry impression af-ter the swelling, not impairing the advance of liquid by forming a barrier, and swelling against external load with a high swelling capacity (retention) is ob-tained. Therefore, the polymer according to the pres-ent invention is particularly suitable for embedding it between paper, non-woven fabrics and in diaper con-structions.
The aftertreated polymer obtained is examined as follows:
1.) Liquid absorption The absorbed amount of liquid per gram of water-swell-able polymer is measured. A weighed polymer quantity is enclosed in a tea bag and dipped into a 0.9% solu-tion of sodium chloride. The amount of absorption is determined after 10 minutes, after the tea bag has been centrifuged at 1400 rpm for 5 minutes in a cen-trifuge having a diameter of 23 cm; the liquid amount absorbed by the tea bag material is deducted.
weight after - weight of the Amount of ~ = absorption (g) tea bag (g) absorption 9 (retention) weight of the polymer (g) ' 2.) Liquid absorption under load The absorption under load (AUL) is determined accord-ing to the method described in European Patent No. 0 339 461, page 7:
The weighed portion of superabsorber is placed in a cylindrical vessel with sieve bottom and the powder is stressed with a punch exerting a pressure of 20 g/cm2.
The cylinder is subsequently placed on a Demand-Ab-sorbency-Testing Device (DAT) and the superabsorber is allowed to suck 0.9~ NaCl-solution for one hour.
ON A WATER-SWELLABLE POLYMER
The present invention relates to a powdery absorbent for aqueous liquids which is based on a water-swell-able polymer not setting up on contact with water or aqueous solutions, such as body liquids, i.e., said water-swellable polymers do not impede the absorption of further liquid by forming a barrier of swollen gel particles and they maintain their swelling capacity under load, as is the case when the polymers are used in diapers or incontinence articles, to a large ex-tent.
The manufacture of water-swellable polymers is known.
A typical method of producing water-swellable polymer particles by inverse suspension polymerization of an aqueous solution of acrylic acid and alkali or ammoni-um acrylate in a hydrocarbon and cross-linking the polymer is described in U.S.-Patent No. 4,698,404.
European patent application No. A1 0 205 674 describes the solvent polymerization of monomers substantially containing acid groups in the presence of an agent having a cross-linking action. After the acid sroups of the polymer have been neutralized by at least 27%
and the polymer gel has been dried, a water-swellable polymer is obtained which has a high gel strength and small amounts of extractable components.
European patent application No. A2 0 312 952 describes the polymerization of carboxyl-groups-containing mono-mers neutralized by at least 20% in the presence of dispersed cross-linking agents.
The continuous copolymerization of an acrylic-acid-comprising monomer solution, wherein the acrylic acid is neutralized by at least 20%, is described in Euro-pean patent application No. A2 0 280 541.
To improve the technical application properties of wa-ter-swellable polymers selected from the group con-sisting of a cross-linked hydrolyzate of an acrylamide copolymer, a hydrolyzate of a cross-linked acryloni-trile copolymer, a cross-linked, partially neutralized acrylic acid polymer, or to adapt them to their par-ticular function, the polymers are frequently sub-jected to a secondary treatment.
European Patent Nos. O 009 977 and 0 001 706, for example, describe the surface coating of particle-shaped water-swellable polymers with hydrophobic com-pounds or polyethers to improve the dispersibility in blood.
U.S.-Patent No. 4,587,308 describes the secondary cross-linkage of water-swellable polymers, dispersed in slightly swollen form, with diglycide ethers, poly-valent metal salts or halogen epoxy compounds.
German OS [Offenlegungsschrift, publication of a Ger-man patent application] No. 34 29 379 describes a wa-ter-absorbing resin obtainable by impregnating a wa-ter-swellable resin with a hydrophilic, reactive, ole-finically unsaturated monomer, or polymer thereof, and a cross-linking agent.
.. . .
U.S.-Patent No. 4.666,975 describes the post-cross-linkage of water-swellable polymers in suspension by reaction with diglycide ethers.
GB 21 19 384 A claims the secondary cross-linkage in the particle surface of water-swellable polymers, the carboxyl groups of which are neutralized to 50 to 99 mol-%, with multifunctional compounds, such as polyols or polyamines.
The secondary cross-linkage in the polymer surface with solutions of polyols is described in DE-OS 35 23 617. The aftertreatment is carried out with polymers whose carboxyl groups are neutralized by 50 to 99 mol-% in the presence of water and a hydrophilic organic solvent.
All these processes strive for improving the liquid transport in a layer of polymer particles or providing a polymer which~ after swelling, does not release the stored liquid on exertion of pressure, e.g., by an in-fant's body on the swollen polymer within a diaper.
However, it is the object not only to improve the liq-uid transport in a layer of water-swellable polymer particles or the capability of the polymer to retain liquid under subsequent pressure when the polymer could swell freely, i.e., without load, but also to provide a water-swellable polymer which is capable of absorbing liquid even against a load. This special ab-sorption property is referred to as absorption under pressure/load in the European Patent O 339 461.
It has been found that water-swellable, carboxyl-groups-containing polymers 50 to 99 mol-% of which are present in neutralized form can be obtained with a ' - ~ ' ' ' :
- , :
high swelling capacity under load, if water-swellable polymers with a low swellability under load are-treat-ed with N-(hydroxyalkyl)~-(meth)-alanine esters and/or the polycondensation products thereof and heated.
It has additionally been found that the elevated-tem-perature secondary treatment of carboxyl-groups-con-taining polymers - which are neutralized by more than 80 mol-% - with polyols or amino alcohols does not, or only under impracticable conditions, result in prod-ucts with improved properties, but that, in contrast to this, treating said polymers neutralized by more than 80 mol-% with N-(hydroxyalkyl)~-(meth)-alanine esters and/or the polycondensation products thereof at elevated temperatures may result in an increase of the swelling capacity under load.
An additional technical advantage of the secondary treatment of water-swellable polymers with N-(hydroxy-alkyl)~-(meth)alanine esters and/or the resulting polyamide or polyamide ethers thereof results from the fact that lower aftertreatment temperatures with a mo-larly identical feedstock of aftertreatment agent or shorter secondary treatment periods at the same tem-perature are necessary to improve the product proper-ties, this is in contrast to the use of polyols or al-kanolamines according to the methods of GB 21 19 384 and DE-OS 35 33 617.
The production of N-(hydroxyalkyl)~-(meth~alanine es-ters and their capabil.ity of forming polyamides or polyamide ethers already at room temperature are de-scribed in detail in Journal of Polymer Science , Part A-1, vol. 6, 1195-1207 (1968) and vol. 7, 889-898 (1969).
The production is carried out by the Michael reaction of alkanols or alkanolamines at (meth)acrylic acid es-ter.
The quantity of N-(hydroxyalkyl)~-(meth)alanine esters and/or their polycondensation products used according to the present invention amounts to 0.001 to 5 p/wt (parts by weight), relative to 100 parts of water-swellable polymer. If more than 5 p/wt are used, the extent of decrease in the swelling capacity (reten-tion) of the polymer is too 'large. The swellability under load is not improved, if the charge is below 0.001 p/wt.
The aftertreatment agents according to the present in-vention are used in aqueous solution. The water serves to dissolve the alcohol-insoluble solid polyamides of the N-(hydroxyalkyl)~(meth)alanine esters and, at the same time, as vehicle for the aftertreatment agents into the water-swellable Polymer particles. The quan-tity of water amounts to 0.1 to 5 p/wt per 100 p/wt of water-swellable polymer. Since the water-swellable polymers which have not been re-treated would set up on contact with the aqueous solutions of the after-treatment agent, additional water-soluble organic di-luents are used in amounts of 0.2 to 10 p/wt per 100 p/wt of water-swellable polymer. The following sub-stances are used as water-soluble organic diluting agents:
a) those evaporating from the solution of the second-ary treatment agent and the water-swellable polymer on heating said mixture, e.g., monofunctional alcohols having the C-number 1-4, acetone, glycol ether, glycol ester and/or b) those which do not evaporate on heating and remain on or in the polymer particle, e.g., butyrolactone, butyrolactam, lactic acid, diacetin.
Since the diluents stated under a) are inflammable and form explosive mixtures which must not come to the at-mosphere, they require some technical measures when the secondary treatment of the water-swellable poly-mers is carried out.
The diluents stated under b) remain on the polymer and do not require special protective measures. However, they may negatively influence the swelling capacity of the aftertreated polymers, when used in larger amounts during the secondary treatment.
The amount of added water-soluble organic diluting agent depends on the amount of water employed. The quantity should be determined such that, after mixing with the water-swellable polymer, a product results which is easy to handle and does not contain aggluti-nated particles.
The solution of the preparation is mixed with the pow-dery, water-swellable, carboxyl-groups-containing pol-ymer and subsequently heated. The powdery polymer may have a spherical shape, obtainable by polymerization of emulsified aqueous monomer solutions, or an irregu-lar shape, obtainable by solvent polymerization, e.g., of a 30% monomer solution comprising 50 to 99 mol-%
alkali acrylate, 50 to 1 mol-% acrylic acid and 0.01 to 0.5 %-wt. of an agent having a cross-linking ac-tion. The particle size of the water-swellable polymer to be treated amounts to 0.05 to 1 mm, preferably 0.1 to 0.8 mm.
20687~9 The mixture consisting of the solution of the agent and the water-swellable polymer is manufactured in the laboratory with ordinary mixers, such as those used in the household. In large-scale production, blade mixers or paddle mixers operating continuously or discontinu-ously are used. The solution of the agent is evenly dosed to the powder preparation or into the powder stream.
The mixture of dissolved, di~uted preparation and wa-ter-swellable polymer is subsequently heated to 100 to 250C, preferably 150 to 210C. The heating tempera-ture and time depend on the amount of agent, with the treatment time in general amounting to at least 5 min.
up to one hour.
The amount of preparation, the mode of feeding, and the treatment temperature are advantageously coordi-nated in such a way that the duration of treatment permits a continuous performance of the process, i.e., that the required heat-up time does not result in too long dwell times within the dryer and the subsequent cooler. Suitable dryers are, e.g., the drying cabinet or the disk dryer.
A water-swellable polymer giving a dry impression af-ter the swelling, not impairing the advance of liquid by forming a barrier, and swelling against external load with a high swelling capacity (retention) is ob-tained. Therefore, the polymer according to the pres-ent invention is particularly suitable for embedding it between paper, non-woven fabrics and in diaper con-structions.
The aftertreated polymer obtained is examined as follows:
1.) Liquid absorption The absorbed amount of liquid per gram of water-swell-able polymer is measured. A weighed polymer quantity is enclosed in a tea bag and dipped into a 0.9% solu-tion of sodium chloride. The amount of absorption is determined after 10 minutes, after the tea bag has been centrifuged at 1400 rpm for 5 minutes in a cen-trifuge having a diameter of 23 cm; the liquid amount absorbed by the tea bag material is deducted.
weight after - weight of the Amount of ~ = absorption (g) tea bag (g) absorption 9 (retention) weight of the polymer (g) ' 2.) Liquid absorption under load The absorption under load (AUL) is determined accord-ing to the method described in European Patent No. 0 339 461, page 7:
The weighed portion of superabsorber is placed in a cylindrical vessel with sieve bottom and the powder is stressed with a punch exerting a pressure of 20 g/cm2.
The cylinder is subsequently placed on a Demand-Ab-sorbency-Testing Device (DAT) and the superabsorber is allowed to suck 0.9~ NaCl-solution for one hour.
3.) Modulus of shear The modulus of shear is measured by means of a Carri-Med-Stress-Rheometer with plate-plate-configuration.
In order to determine the modulus of shear 1 9 water-absorbing resin is allowed to swell for one hour in 28 9 0.9% NaCl-solution, then the modulus of shear is 20687~9 measured in the swollen gel in dependence on the fre-quency (0.1 - 10 Hz). The value at 10 Hz is indicated as storage modulus G' in N/m2.
The present invention will be illustrated in more de-tail by the following examples.
1.) Production of the agents used according to the present invention for the water-swellable polymers (N-thydroxyalkyl)~-(meth)-alanine esters and the polycondensation products thereof:
a) Agent A
10 9 ethyl acrylate and 10 9 ethanol are weighed into a flask and 6.15 9 ethanolamine are added under stir-ring. The solution which is warming up is allowed to stand for 15 hours to terminate reaction.
b) Agent B
10 9 methyl methacrylate and 6.15 9 ethanolamine are reacted at 40OC for 15 hours under stirring.
c) Agent C
In a flask 13 9 2-hydroxypropyl acrylate-and 10 9 eth-anol are stirred-up with 6.2 9 ethanolamine at room temperature. The solution is allowed to stand for 18 hours to terminate reaction.
d) Agent D
Preparation A, which is a clear solution, is allowed to stand for 14 days at room temperature. During this `' .
1 o period, a fine white precipitate forms which is solu-ble in alcohol or water. The homogenized suspension is used to treat the polymers.
e) Agent E
100 9 ethyl acrylate and 100 9 ethanol are mixed in an agitated flask with 61 9 ethanolamine; after 18 hours in a rotary evaporator at a bath temperature of 80C
and a pressure of 20 mbar, the clear solution is lib-erated from volatile components. An oil which is slightly turbid at room temperature and highly viscous is obtained which becomes waxy during standing.
f) Agent F
100 9 ethyl acrylate are added to 61 9 monoethanol-amine in 200 ml methanol within an agitated flask, the mixture is stirred for 8 hours. 800 ml methanol and 14 9 25% potassium methylate solution are added into the agitated flask and stirring is continued for 80 hours.
The resulting white precipitate is filtered off, stir-red up in 500 ml methanol and filtered off once again.
The filter cake is dried at 50C and 25 mbar.
73.2 9 white powder are obtained, it melts between 195 and 203C.
g) Agent G
1000 ml tetrahydrofuran are placed in an agitated flask; 14 9 25% potassium methylate solution, 62 9 monoethanolamine and 100 9 ethyl acrylate are added under stirring. The initially clear solution becomes cloudy and then a soft polycondensate settles down at 20687~9 l l the bottom of the reactor. The supernatant solution is poured off and the viscous polycondensate is liberated from adhering volatile components at 25 mbar and 50OC.
Total amine: 2.8 mmol~g.
2) Treatment of the water-swellable polymers according to the present invention:
Example 1 and 2 and Comoarative Examples 1 to 3:
A water-swellable polymer having the particle size of 0.2 to 0.8 mm, obtained by polymerizing a 29% monomer solution of 90 mol-% sodium acrylate and 10 mol-%
acrylic acid in the presence of 0.25%-wt. trimethylol-propane-triacrylate (relative to acrylic acid) having an absorbency (retention) for 0.9% NaCl-solution of 40.0 9/9 and an absorbency under load (AUL) of 6.9 9/9 .
100 9 of the water-swellable polymer are placed in a 500 ml plastic cup and mixed under strong stirring with a single-armed domestic mixer with aftertreatment agents, water, and organic diluting agents (the amounts are stated in Table 1) within about 3 min. The mixture is spread in a glass dish at a layer thickness of 5 to 10 mm and heated in a recirculating air dryer.
The drying periods and temperatures as well as the test results are stated in Table 1. Ethanolamine and glycerol were used as prepartion agent in the compara-tive examples 1 to 3.
':
206~749 "
Table 1 : Exam. Water Diluent Agent Time Temp. AUL Retention No. (g) (g) (g) (min) (oC) (9/9) (9/9) .
- methanol E 10 19024.0 32.6 ; 1 2.02.8 1.3 methanol A
2 2.02.4 1.0 20 19030.9 33.2 Comparative Example methanol ethanolamine 1 2.02.8 0.5 10 1906.9 39.6 " " " 20 lgO7.5 40.7 methanol glycerol 2 2.02.8 0.5 20 1908.2 38.1 " " " 60 1908.6 39.6 3 2.02.8 1.0 30 19013.8 37.9 .
ExamDles 3 to 5 A polymer with the grain size 0.15 to 0.8 mm, obtained by solvent polymerization as in Example 1, except for the fact that the monomer mixture consisted of 70 mol-% of sodium acrylate and 30 mol-~ of acrylic acid. The polymer has a retention of 39.5 9/9 and an AUL of 7.6 9t9 .
100 9 of this powdery polymer are mixed with solutions of the preparation F as in Example 1 and heated. The treatment conditions and test results are listed in Table 2.
2~68749 Table_2 Exam. Water Diluent Agent Time Temp. AUL Retention No. (g) (g) (g) ~min) (C) (g/g) (9/9) methanol 3 2.02.8 0.30 15 180 25.8 37.3 methanol 4 2.02.8 0.15 15 180 28.6 37.6 ethanol 2.02.8 0.05 20 190 32.6 38.1 Example 6 100 9 of the water-swellable polymer used in Example 3 are mixed with a solution of 0.1 9 of agent E, 2 9 wa-ter, and 1.0 9 2-pyrrolidone as in Example 1 and heated.
Treatment temp. time AUL Retention (C) (min) (9/9) (9/9) 190 10 26.2 40.4 190 15 30.4 36.2 190 20 29.2 34.9 Exam~les 7 to 12 and Comparative ExamPle 4 The mixture is prepared with 100 9 polymer according to Example 3, the conditions, secondary treatment agents, treatment temperatures and times are stated in Table 3.
206g749 T ble 3 .
Exam. Water Solvent Agent Temp. Time AUL Retention No. (g) (9) (9) (C) (min) (g/g) (9/9) A
7 2.0 - 8.58 150 1027.9 39.0 methanol A
8 2.0 2 2.11 180 1030.3 34.1 methanol A
9 2.0 2 1.05 180 1431.1 36.0 methanol A
2.0 2 0.52 180 2028.7 36.1 methanol B
11 2.0 2 5.27 150 6031.3 35.4 -ethanol C
12 2.0 2 2.4 150 3027.3 33.6 Comparative Example ethanol ethanolamine 4 2.0 3.85 0.5 150 30 9.0 2.0 3.85 0.5 150 6010.5 Example 13 100 9 of the water-swellable polymer used in Example 3 (G' = 1800 N/mZ) are mixed with 5.05 9 of a solution of 1.05 9 of the homogenized suspension of aftertreat-ment agent D, 2.0 9 water, and 2.0 9 methanol and heated in the recirculating air dryer.
1 ~, Treatment time temp. AUL Retention G' (min) (oC) (9/9) (9/9) (N/m2) 10 180 26.8 36.7 2350 Exam~les 14 to 16 100 9 of a cross-linked polyacrylic acid the carboxyl groups of which are present by 60 mol-% in neutralized form and having a particle size of 0.2 to 0.85 mm, tradename FAVOR 922 of Chemische Fabrik Stockhausen GmbH, Krefeld, FRG, are mixed with a solution of prep-aration A in 2.0 9 water and 2.0 9 methanol as in Ex-ample 1 and heated in a recirculating air dryer.
Exam.Agent Temp. Time AULRetention No. (9) (C) (min)(g/g)(g/9) FAVOR - - - 9.3 41.9 14 2.1 180 10 25.1 30.2 4.2 160 10 26.4 34.5 16 4.2 150 15 28.2 34.1 Exam~le 17 1500 9 water-swellable polymer of the particle size 0.15 to 0.85 mm, manufactured by polymerization of a 29% solution of 70 mol-~ sodium acrylate, 30 mol-%
acrylic acid and 0.17 %-wt. of trimethylol-propane-triacrylate (relative to acrylic acid) with a reten-.. . ~ . .
:' ' - -. .- ' :
20687~9 :`
tion of 44.8 9/9 and an AUL of 7.2 9/9 are prepared in a Drais-mixer. A solution of 1.5 9 agent E, 30 9 wa-ter, and 15 9 2-pyrrolidone is added dropwise into the moved powder bed. The resulting mixture is heated in a fee-falling mixer which has been preheated to 210C.
The heating-up times, temperatures, and the test re-sults are listed in Table 4.
Table 4 , Time Temperature ' AUL Retention (min) (oC) (9/9) (9/9) 146 ~ heating-up period 183 30.2 40.4 185 29.6 38.6 186 28.7 37.8 .
ExamPle 18 100 9 of the water-swellable polymer used in Example 3 are mixed with a solution of 0.3 9 agent G in 2.0 9 water and 2.8 9 methanol; the mixture is spread out in a glass dish and stored in a drying cabinet of 190C
for 15 min. The product cooled to room temperature does not block during the swelling, has an AUL of 33.5 9/9 and a retention of 37.7 9/9.
l7 Exam _e_19 100 9 of the water-swellable polymer used in Example 3 are mixed with a solution of 0.1 9 agent E in 2.0 9 water and l.0 9 diacetin. The powdery product is placed in a drying cabinet preheated to 190C.
After cooling, an AUL of 29.9 9/9 is measured.
ExamDle 20 A cross-linked, water-swellable polymer having a par-ticle size of 0.15 to 0.80 mm and the composition ac-cording to Example 3 is used. The polymer has a reten-tion of 35.5 9/9, an AUL of 9.4 9/9 and a storage mod-ulus of 2600 N/mZ.
A mixture of 1.5 9 preparation, manufactured like agent A without using ethanol as diluent, 30 9 water and 30 9 diacetin is mixed as described in Example 17 with 1500 9 of the powdery polymer and heated. After a treatment period of 20 min at 183 to 185C, the poly-mer exhibits the following characteristics:
Retention = 30.7 9/9 AUL = 31.1 9/9 G' = 5300 N~m2 ExamDle 21 100 9 of a cross-linked polyacrylic acid, the carboxyl groups of which are present in neutralized form by 70 mol-~, and having a retention of 47.5 9/9 and an AUL
of 8.4 9~9, are treated with 4.1 9 of the treatment mixture according to Example 20 and stored at a layer thickness of 3 mm in a drying cabinet preheated to 240OC for lO min.
The obtained polymer has a retention of 35.5 9/9 and an AUL of 24.4 9/9.
It is understood that the specification and examples are illustrative but not limitative of the present in-vention and that other embodiments within the spirit and scope of the invention will suggest themselves to those skilled in the art.
In order to determine the modulus of shear 1 9 water-absorbing resin is allowed to swell for one hour in 28 9 0.9% NaCl-solution, then the modulus of shear is 20687~9 measured in the swollen gel in dependence on the fre-quency (0.1 - 10 Hz). The value at 10 Hz is indicated as storage modulus G' in N/m2.
The present invention will be illustrated in more de-tail by the following examples.
1.) Production of the agents used according to the present invention for the water-swellable polymers (N-thydroxyalkyl)~-(meth)-alanine esters and the polycondensation products thereof:
a) Agent A
10 9 ethyl acrylate and 10 9 ethanol are weighed into a flask and 6.15 9 ethanolamine are added under stir-ring. The solution which is warming up is allowed to stand for 15 hours to terminate reaction.
b) Agent B
10 9 methyl methacrylate and 6.15 9 ethanolamine are reacted at 40OC for 15 hours under stirring.
c) Agent C
In a flask 13 9 2-hydroxypropyl acrylate-and 10 9 eth-anol are stirred-up with 6.2 9 ethanolamine at room temperature. The solution is allowed to stand for 18 hours to terminate reaction.
d) Agent D
Preparation A, which is a clear solution, is allowed to stand for 14 days at room temperature. During this `' .
1 o period, a fine white precipitate forms which is solu-ble in alcohol or water. The homogenized suspension is used to treat the polymers.
e) Agent E
100 9 ethyl acrylate and 100 9 ethanol are mixed in an agitated flask with 61 9 ethanolamine; after 18 hours in a rotary evaporator at a bath temperature of 80C
and a pressure of 20 mbar, the clear solution is lib-erated from volatile components. An oil which is slightly turbid at room temperature and highly viscous is obtained which becomes waxy during standing.
f) Agent F
100 9 ethyl acrylate are added to 61 9 monoethanol-amine in 200 ml methanol within an agitated flask, the mixture is stirred for 8 hours. 800 ml methanol and 14 9 25% potassium methylate solution are added into the agitated flask and stirring is continued for 80 hours.
The resulting white precipitate is filtered off, stir-red up in 500 ml methanol and filtered off once again.
The filter cake is dried at 50C and 25 mbar.
73.2 9 white powder are obtained, it melts between 195 and 203C.
g) Agent G
1000 ml tetrahydrofuran are placed in an agitated flask; 14 9 25% potassium methylate solution, 62 9 monoethanolamine and 100 9 ethyl acrylate are added under stirring. The initially clear solution becomes cloudy and then a soft polycondensate settles down at 20687~9 l l the bottom of the reactor. The supernatant solution is poured off and the viscous polycondensate is liberated from adhering volatile components at 25 mbar and 50OC.
Total amine: 2.8 mmol~g.
2) Treatment of the water-swellable polymers according to the present invention:
Example 1 and 2 and Comoarative Examples 1 to 3:
A water-swellable polymer having the particle size of 0.2 to 0.8 mm, obtained by polymerizing a 29% monomer solution of 90 mol-% sodium acrylate and 10 mol-%
acrylic acid in the presence of 0.25%-wt. trimethylol-propane-triacrylate (relative to acrylic acid) having an absorbency (retention) for 0.9% NaCl-solution of 40.0 9/9 and an absorbency under load (AUL) of 6.9 9/9 .
100 9 of the water-swellable polymer are placed in a 500 ml plastic cup and mixed under strong stirring with a single-armed domestic mixer with aftertreatment agents, water, and organic diluting agents (the amounts are stated in Table 1) within about 3 min. The mixture is spread in a glass dish at a layer thickness of 5 to 10 mm and heated in a recirculating air dryer.
The drying periods and temperatures as well as the test results are stated in Table 1. Ethanolamine and glycerol were used as prepartion agent in the compara-tive examples 1 to 3.
':
206~749 "
Table 1 : Exam. Water Diluent Agent Time Temp. AUL Retention No. (g) (g) (g) (min) (oC) (9/9) (9/9) .
- methanol E 10 19024.0 32.6 ; 1 2.02.8 1.3 methanol A
2 2.02.4 1.0 20 19030.9 33.2 Comparative Example methanol ethanolamine 1 2.02.8 0.5 10 1906.9 39.6 " " " 20 lgO7.5 40.7 methanol glycerol 2 2.02.8 0.5 20 1908.2 38.1 " " " 60 1908.6 39.6 3 2.02.8 1.0 30 19013.8 37.9 .
ExamDles 3 to 5 A polymer with the grain size 0.15 to 0.8 mm, obtained by solvent polymerization as in Example 1, except for the fact that the monomer mixture consisted of 70 mol-% of sodium acrylate and 30 mol-~ of acrylic acid. The polymer has a retention of 39.5 9/9 and an AUL of 7.6 9t9 .
100 9 of this powdery polymer are mixed with solutions of the preparation F as in Example 1 and heated. The treatment conditions and test results are listed in Table 2.
2~68749 Table_2 Exam. Water Diluent Agent Time Temp. AUL Retention No. (g) (g) (g) ~min) (C) (g/g) (9/9) methanol 3 2.02.8 0.30 15 180 25.8 37.3 methanol 4 2.02.8 0.15 15 180 28.6 37.6 ethanol 2.02.8 0.05 20 190 32.6 38.1 Example 6 100 9 of the water-swellable polymer used in Example 3 are mixed with a solution of 0.1 9 of agent E, 2 9 wa-ter, and 1.0 9 2-pyrrolidone as in Example 1 and heated.
Treatment temp. time AUL Retention (C) (min) (9/9) (9/9) 190 10 26.2 40.4 190 15 30.4 36.2 190 20 29.2 34.9 Exam~les 7 to 12 and Comparative ExamPle 4 The mixture is prepared with 100 9 polymer according to Example 3, the conditions, secondary treatment agents, treatment temperatures and times are stated in Table 3.
206g749 T ble 3 .
Exam. Water Solvent Agent Temp. Time AUL Retention No. (g) (9) (9) (C) (min) (g/g) (9/9) A
7 2.0 - 8.58 150 1027.9 39.0 methanol A
8 2.0 2 2.11 180 1030.3 34.1 methanol A
9 2.0 2 1.05 180 1431.1 36.0 methanol A
2.0 2 0.52 180 2028.7 36.1 methanol B
11 2.0 2 5.27 150 6031.3 35.4 -ethanol C
12 2.0 2 2.4 150 3027.3 33.6 Comparative Example ethanol ethanolamine 4 2.0 3.85 0.5 150 30 9.0 2.0 3.85 0.5 150 6010.5 Example 13 100 9 of the water-swellable polymer used in Example 3 (G' = 1800 N/mZ) are mixed with 5.05 9 of a solution of 1.05 9 of the homogenized suspension of aftertreat-ment agent D, 2.0 9 water, and 2.0 9 methanol and heated in the recirculating air dryer.
1 ~, Treatment time temp. AUL Retention G' (min) (oC) (9/9) (9/9) (N/m2) 10 180 26.8 36.7 2350 Exam~les 14 to 16 100 9 of a cross-linked polyacrylic acid the carboxyl groups of which are present by 60 mol-% in neutralized form and having a particle size of 0.2 to 0.85 mm, tradename FAVOR 922 of Chemische Fabrik Stockhausen GmbH, Krefeld, FRG, are mixed with a solution of prep-aration A in 2.0 9 water and 2.0 9 methanol as in Ex-ample 1 and heated in a recirculating air dryer.
Exam.Agent Temp. Time AULRetention No. (9) (C) (min)(g/g)(g/9) FAVOR - - - 9.3 41.9 14 2.1 180 10 25.1 30.2 4.2 160 10 26.4 34.5 16 4.2 150 15 28.2 34.1 Exam~le 17 1500 9 water-swellable polymer of the particle size 0.15 to 0.85 mm, manufactured by polymerization of a 29% solution of 70 mol-~ sodium acrylate, 30 mol-%
acrylic acid and 0.17 %-wt. of trimethylol-propane-triacrylate (relative to acrylic acid) with a reten-.. . ~ . .
:' ' - -. .- ' :
20687~9 :`
tion of 44.8 9/9 and an AUL of 7.2 9/9 are prepared in a Drais-mixer. A solution of 1.5 9 agent E, 30 9 wa-ter, and 15 9 2-pyrrolidone is added dropwise into the moved powder bed. The resulting mixture is heated in a fee-falling mixer which has been preheated to 210C.
The heating-up times, temperatures, and the test re-sults are listed in Table 4.
Table 4 , Time Temperature ' AUL Retention (min) (oC) (9/9) (9/9) 146 ~ heating-up period 183 30.2 40.4 185 29.6 38.6 186 28.7 37.8 .
ExamPle 18 100 9 of the water-swellable polymer used in Example 3 are mixed with a solution of 0.3 9 agent G in 2.0 9 water and 2.8 9 methanol; the mixture is spread out in a glass dish and stored in a drying cabinet of 190C
for 15 min. The product cooled to room temperature does not block during the swelling, has an AUL of 33.5 9/9 and a retention of 37.7 9/9.
l7 Exam _e_19 100 9 of the water-swellable polymer used in Example 3 are mixed with a solution of 0.1 9 agent E in 2.0 9 water and l.0 9 diacetin. The powdery product is placed in a drying cabinet preheated to 190C.
After cooling, an AUL of 29.9 9/9 is measured.
ExamDle 20 A cross-linked, water-swellable polymer having a par-ticle size of 0.15 to 0.80 mm and the composition ac-cording to Example 3 is used. The polymer has a reten-tion of 35.5 9/9, an AUL of 9.4 9/9 and a storage mod-ulus of 2600 N/mZ.
A mixture of 1.5 9 preparation, manufactured like agent A without using ethanol as diluent, 30 9 water and 30 9 diacetin is mixed as described in Example 17 with 1500 9 of the powdery polymer and heated. After a treatment period of 20 min at 183 to 185C, the poly-mer exhibits the following characteristics:
Retention = 30.7 9/9 AUL = 31.1 9/9 G' = 5300 N~m2 ExamDle 21 100 9 of a cross-linked polyacrylic acid, the carboxyl groups of which are present in neutralized form by 70 mol-~, and having a retention of 47.5 9/9 and an AUL
of 8.4 9~9, are treated with 4.1 9 of the treatment mixture according to Example 20 and stored at a layer thickness of 3 mm in a drying cabinet preheated to 240OC for lO min.
The obtained polymer has a retention of 35.5 9/9 and an AUL of 24.4 9/9.
It is understood that the specification and examples are illustrative but not limitative of the present in-vention and that other embodiments within the spirit and scope of the invention will suggest themselves to those skilled in the art.
Claims (7)
1. A powdery absorbent for aqueous liquids which is based on a water-swellable powdery polymer and obtain-able by manufacturing and heating a mixture consisting of 100 parts by weight of at least one water-swell-able, carboxyl-groups-containing polymer comprising at least 0.2 equivalents of carboxyl groups per 100 parts by weight, 50 to 99 mol-% of which being present in neutralized form and a) 0.001 to 5 parts by weight, preferably 0.05 to 2 parts by weight, N-(hydroxyalkyl).beta.-(meth)-alanine es-ters and/or b) 0.001 to 5 parts by weight, preferably 0.05 to 2 parts by weight, polycondensation products of a) in c) 0.1 to 5 parts by weight water and d1) 0.2 to 10 parts by weight of a water-miscible or-ganic diluting agent evaporating on heating the mix-ture and/or d2) 0.2 to 10 parts by weight of a water-miscible or-ganic diluent which does not evaporate on heating the mixture.
2. The water-swellable agent according to claim 1 ob-tained by heating the mixture according to claim 1 to 100 to 250°C, preferably to 150 to 210°C.
3. The water-swellable agent according to claim 1 and 2 obtained by the use of .beta.-(meth)-alanine esters sub-stituted at the nitrogen atom by hydroxy-C1-C6-alkyl groups.
4. The water-swellable agent according to any one or claims 1 to 3 obtained by using N-(hydroxyalkyl)-sub-stituted .beta.-(meth)alanine-C1-C6-alkyl esters or -C1-C6 -hydroxyalkyl esters.
5. The water-swellable agent according to any one of claims 1 to 4 obtained by using water-soluble polyam-ides of N-(hydroxyalkyl).beta.(meth)-alanine esters.
6. The water-swellable agent according to any one of claims 1 to 4 obtained by using water-soluble polyam-ide ethers of N-(hydroxyalkyl).beta.-(meth-)alanine esters.
7. The water-swellable agent according to any one of claims 1 to 6 in which at least 80 mol-% of the poly-mer are neutralized.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP4116428.8 | 1991-05-18 | ||
| DE4116428A DE4116428C2 (en) | 1991-05-18 | 1991-05-18 | Powdered absorbent for aqueous liquids based on a water-swellable polymer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2068749A1 true CA2068749A1 (en) | 1992-11-19 |
Family
ID=6432029
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002068749A Abandoned CA2068749A1 (en) | 1991-05-18 | 1992-05-15 | Pulverized absorbent material for aqueous liquids based on a water-swellable polymer |
Country Status (10)
| Country | Link |
|---|---|
| US (1) | US5229466A (en) |
| EP (1) | EP0514724B1 (en) |
| JP (1) | JP3177859B2 (en) |
| AT (1) | ATE108092T1 (en) |
| CA (1) | CA2068749A1 (en) |
| DE (2) | DE4116428C2 (en) |
| DK (1) | DK0514724T3 (en) |
| ES (1) | ES2036159T3 (en) |
| GR (1) | GR930300012T1 (en) |
| TW (1) | TW203619B (en) |
Families Citing this family (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3414778B2 (en) * | 1993-01-26 | 2003-06-09 | 株式会社日本触媒 | Surface treatment method for water absorbent resin |
| US5314420A (en) * | 1993-09-17 | 1994-05-24 | Nalco Chemical Company | Superabsorbent polymer having improved absorption rate and absorption under pressure |
| US5451613A (en) * | 1993-09-17 | 1995-09-19 | Nalco Chemical Company | Superabsorbent polymer having improved absorption rate and absorption under pressure |
| DE19601763A1 (en) * | 1996-01-19 | 1997-07-24 | Hoechst Ag | Use of surfactants in the drying of hydrophilic, highly swellable hydrogels |
| DE19624419A1 (en) * | 1996-06-19 | 1998-01-02 | Haarmann & Reimer Gmbh | Desiccant containing fragrance |
| DE19753601A1 (en) | 1997-12-03 | 1999-06-10 | Behr Gmbh & Co | Cold storage, in particular for a motor vehicle |
| US6872384B1 (en) | 1998-02-23 | 2005-03-29 | Life Medical Sciences, Inc. | Treatment of trauma |
| DE19825486C2 (en) | 1998-06-08 | 2000-07-06 | Stockhausen Chem Fab Gmbh | Water-absorbing polymers with supramolecular cavity molecules, process for their preparation and their use |
| US6187828B1 (en) | 1998-11-24 | 2001-02-13 | Basf Corporation | Continuous process for manufacturing superabsorbent polymer |
| DE19909653A1 (en) | 1999-03-05 | 2000-09-07 | Stockhausen Chem Fab Gmbh | Powdery, crosslinked, aqueous liquids and blood-absorbing polymers, processes for their preparation and their use |
| US6565981B1 (en) | 1999-03-30 | 2003-05-20 | Stockhausen Gmbh & Co. Kg | Polymers that are cross-linkable to form superabsorbent polymers |
| PL364694A1 (en) * | 1999-04-06 | 2004-12-13 | Sca Hygiene Products Zeist B.V. | Hygienic absorbent with odour control |
| US6514615B1 (en) | 1999-06-29 | 2003-02-04 | Stockhausen Gmbh & Co. Kg | Superabsorbent polymers having delayed water absorption characteristics |
| US20030007951A1 (en) * | 2000-08-23 | 2003-01-09 | Richard Franklin | Treatment of trauma |
| EP1320553A4 (en) * | 2000-08-23 | 2006-03-15 | Phairson Medical Inc | Novel polymer compounds |
| DE10041392A1 (en) * | 2000-08-23 | 2002-03-07 | Stockhausen Chem Fab Gmbh | Water-soluble homopolymers and copolymers with improved environmental compatibility |
| US7101946B2 (en) * | 2002-02-14 | 2006-09-05 | Stockhausen Gmbh | Water-absorbing polymers having interstitial compounds, a process for their production, and their use |
| US7026373B2 (en) * | 2002-05-06 | 2006-04-11 | Stockhausen Gmbh | Polyamphoteric superabsorbent copolymers |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NZ188633A (en) * | 1977-10-18 | 1980-10-24 | Unilever Ltd | Absorbent material surface-treated with polyether |
| JPS6018690B2 (en) * | 1981-12-30 | 1985-05-11 | 住友精化株式会社 | Method for improving water absorbency of water absorbent resin |
| JPS58180233A (en) * | 1982-04-19 | 1983-10-21 | Nippon Shokubai Kagaku Kogyo Co Ltd | Absorbing agent |
| US4734478A (en) * | 1984-07-02 | 1988-03-29 | Nippon Shokubai Kagaku Kogyo Co., Ltd. | Water absorbing agent |
| US5104909A (en) * | 1989-09-21 | 1992-04-14 | W. R. Grace & Co.-Conn. | Water-absorbent, high capacity polyurethane foams |
| US5164459A (en) * | 1990-04-02 | 1992-11-17 | Nippon Shokubai Kagaku Kogyo Co., Ltd. | Method for treating the surface of an absorbent resin |
-
1991
- 1991-05-18 DE DE4116428A patent/DE4116428C2/en not_active Expired - Fee Related
-
1992
- 1992-05-08 DE DE59200265T patent/DE59200265D1/en not_active Expired - Fee Related
- 1992-05-08 DK DK92107810.1T patent/DK0514724T3/en active
- 1992-05-08 EP EP92107810A patent/EP0514724B1/en not_active Expired - Lifetime
- 1992-05-08 AT AT92107810T patent/ATE108092T1/en not_active IP Right Cessation
- 1992-05-08 ES ES92107810T patent/ES2036159T3/en not_active Expired - Lifetime
- 1992-05-15 CA CA002068749A patent/CA2068749A1/en not_active Abandoned
- 1992-05-18 US US07/884,344 patent/US5229466A/en not_active Expired - Lifetime
- 1992-05-18 JP JP12491392A patent/JP3177859B2/en not_active Expired - Fee Related
- 1992-05-19 TW TW081103881A patent/TW203619B/zh active
-
1993
- 1993-04-28 GR GR930300012T patent/GR930300012T1/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| JPH05138019A (en) | 1993-06-01 |
| ES2036159T3 (en) | 1994-10-01 |
| TW203619B (en) | 1993-04-11 |
| EP0514724B1 (en) | 1994-07-06 |
| ES2036159T1 (en) | 1993-05-16 |
| ATE108092T1 (en) | 1994-07-15 |
| DE4116428C2 (en) | 1995-04-13 |
| DE59200265D1 (en) | 1994-08-11 |
| JP3177859B2 (en) | 2001-06-18 |
| GR930300012T1 (en) | 1993-04-28 |
| DE4116428A1 (en) | 1992-11-19 |
| EP0514724A1 (en) | 1992-11-25 |
| US5229466A (en) | 1993-07-20 |
| DK0514724T3 (en) | 1994-11-14 |
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